package android_serialport_api;

import android.util.Log;

import java.io.File;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class SerialPort {

    private static final String TAG = "SerialPort";
    public FileDescriptor mFd;
    private FileInputStream mFileInputStream;
    private FileOutputStream mFileOutputStream;

    public SerialPort(File device, int baudrate, int flags) throws Exception {

        //检查访问权限，如果没有读写权限，进行文件操作，修改文件访问权限

		/* Check access permission */
		if (!device.canRead() || !device.canWrite()) {
			try {
				/* Missing read/write permission, trying to chmod the file */
				Process su;
				su = Runtime.getRuntime().exec("/system/bin/su");
				String cmd = "chmod 666 " + device.getAbsolutePath() + "\n"
						+ "exit\n";
				su.getOutputStream().write(cmd.getBytes());
				if ((su.waitFor() != 0) || !device.canRead()
						|| !device.canWrite()) {
					throw new SecurityException();
				}
			} catch (Exception e) {
				e.printStackTrace();
				//throw new SecurityException();
                throw new Exception();
			}
		}

        mFd = open(device.getAbsolutePath(), baudrate, flags);

        if (mFd == null) {
            Log.e(TAG, "native open returns null");
            throw new IOException();
        }

        mFileInputStream = new FileInputStream(mFd);
        mFileOutputStream = new FileOutputStream(mFd);
    }

    // Getters and setters
    public InputStream getInputStream() {
        return mFileInputStream;
    }

    public OutputStream getOutputStream() {
        return mFileOutputStream;
    }


    // JNI(调用java本地接口，实现串口的打开和关闭)
    private native static FileDescriptor open(String path, int baudrate, int flags);
    public native void close();
    static {//加载jni下的C文件库
        Log.d(TAG, "loading serial_port.so");
        try {
            System.loadLibrary("serial_port");
        }catch (UnsatisfiedLinkError e){
            Log.e(TAG, "加载本地库失败"+e.getMessage());
        }
    }
}
